时间:2018-12-24 作者:英语课 分类:2016年Scientific American(十二)月


英语课

 


When you spill a liquid on the ground, it splashes. But if you’re a guy using a urinal, or, more important, if the liquid is dangerous, say, an infected blood sample, you want to limit splashing. In other words:


“If an accident happens, you want the drop to fall onto the surface and that’s it. It just stays there as a single body.”


Alfonso Castrejo?n-Pita, an engineering professor at Oxford 1 University.


“So you could imagine the situation of having your [lab] bench covered with these kinds of materials so they become safer. And the same for a kitchen. Now you’re in a kitchen, you are handling raw chicken, and the last thing you want is to have splashes, where you could be transmitting salmonella or these kinds of ugly things that you could get when you are handling raw meat.”


He and his colleagues found that the softer the surface the smaller the splash. Their study is in the journal Physical Review Letters. [Christopher J. Howland et al., It’s Harder to Splash on Soft Solids]


The researchers prepared a bunch of increasingly squishy silicone surfaces and released drops of ethanol onto them from different heights. They captured video of the splashes with a super-slow-motion camera that records more than 100,000 frames per second. And they found that the drops eventually stopped splashing on the softest surfaces.


So far that all sounds predictable. But computer models of the splashes revealed interesting details.


At the moment the blob of liquid makes contact with the surface, the bottom of the drop flattens 2 out and the pressure increases. The ring of pressure spreads towards the drop’s edges. If the surface is too hard, the ring of high pressure creates tiny droplets 3 that explode from the main drop’s edges. But the softest surfaces deform 4 in response to the drop hitting them—and that prevents the pressure from getting high enough to cause that explosion.


Sadly, you won’t see squishy coatings on urinals just yet, or in your laboratories—anti-splash materials are too frail 5


“The softest ones are quite delicate so you wouldn’t be able to make a laboratory bench with them, they’d get damaged quite quickly.”


So we’d need soft coating materials robust 6 enough to withstand daily wear before the splash is relegated 7 to history’s trash bin…or toilet.


—Ryan Mandelbaum



1 Oxford
n.牛津(英国城市)
  • At present he has become a Professor of Chemistry at Oxford.他现在已是牛津大学的化学教授了。
  • This is where the road to Oxford joins the road to London.这是去牛津的路与去伦敦的路的汇合处。
2 flattens
变平,使(某物)变平( flatten的第三人称单数 ); 彻底打败某人,使丢脸; 停止增长(或上升); (把身体或身体部位)紧贴…
  • After Oxford the countryside flattens out. 过了牛津以远乡村逐渐平坦。
  • The graph flattens out gradually after a steep fall. 图表上的曲线突降之后逐渐趋于平稳。
3 droplets
n.小滴( droplet的名词复数 )
  • Droplets of sweat were welling up on his forehead. 他额头上冒出了滴滴汗珠。 来自辞典例句
  • In constrast, exhaled smoke contains relatively large water droplets and appears white. 相反,从人嘴里呼出的烟则包含相当大的水滴,所以呈白色。 来自辞典例句
4 deform
vt.损坏…的形状;使变形,使变丑;vi.变形
  • Shoes that are too tight deform the feet.(穿)太紧的鞋子会使脚变形。
  • Ice crystals begin to deform measurably.冰晶就产生某种程度的变形了。
5 frail
adj.身体虚弱的;易损坏的
  • Mrs. Warner is already 96 and too frail to live by herself.华纳太太已经九十六岁了,身体虚弱,不便独居。
  • She lay in bed looking particularly frail.她躺在床上,看上去特别虚弱。
6 robust
adj.强壮的,强健的,粗野的,需要体力的,浓的
  • She is too tall and robust.她个子太高,身体太壮。
  • China wants to keep growth robust to reduce poverty and avoid job losses,AP commented.美联社评论道,中国希望保持经济强势增长,以减少贫困和失业状况。
7 relegated
v.使降级( relegate的过去式和过去分词 );使降职;转移;把…归类
  • She was then relegated to the role of assistant. 随后她被降级做助手了。
  • I think that should be relegated to the garbage can of history. 我认为应该把它扔进历史的垃圾箱。 来自《现代汉英综合大词典》
学英语单词
2-methylcortisol
aceraius grandis
Aconitum refracticarpum
allantois chorioidea
aquachloral
arsecheek
avant-gardists
back-channeled
be better of
bean tree
Biankouma
body-thrusts
buarques
bwe
C-Prolog
cable distribution point
Chattertonian
claisen para-rearrangement
coati-mundi
colour screw
Crookes' lens
cumulative error
cylinder cover bolt
date of clearance
dibutyryl
Diphyllobothrium erinacei
diplosomites
dome cap
drip gasoline
drywell ambient temperature
error locating
Euro share market
exhibition space
famale worker
fineberg
flunk
foam in hibitors
foreign exchange option
furnace transformer
gross out
half-bottles
heavy lorry
heterodyne repeater
household word
immanacled
income tax authority
intermodal freight terminal
johann maier ecks
josher
khanaqin
Kundsen-langmuir equation
Kutta-Joukowski airfoil
line broadening
linearly equivalence
lorente
lump salt
mating plug
melomelus
Middeldorpf's triangle
near-optimality
neurogenin
non-parametric cointegration
non-provisional
normal atmosphere
nucleus of the solitary tract
nurserygirl
Odawara
orbitosphenoids
Oto-Manguean
owner-like
phase contour
pig pile
plocamium telfairiae
Plutonian
positive vector
pressure-feed oiling
pullulatings
rabbet line
residual noise
reverse intergenerational influence
rodder
sael
sales record
sayan
scrambly
Silicon Wadi
single-action pressing
spongy brake pedal
structural basis
submolecule
sunk-in
Talodex
test harnesses
thunder thighs
torcious
transition state,transition complex
trimmed in bunker
unaccused
unbenzoled petrol
white mahogany
whitenest
zoocoenology